bnxt_en: Reduce maximum ring pages if page size is 64K.

The chip supports 4K/8K/64K page sizes for the rings and we try to
match it to the CPU PAGE_SIZE.  The current page size limits for the rings
are based on 4K/8K page size. If the page size is 64K, these limits are
too large.  Reduce them appropriately.

Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>